# Control of spectral characteristics of spin-current auto-oscillator by electric field

## TL;DR

This paper demonstrates that electrostatic gating can effectively tune the spectral properties of spin-current auto-oscillators by modifying surface anisotropy and spin-orbit torques, enabling electrically controllable microwave nano-oscillators.

## Contribution

It introduces a method to control magnetization auto-oscillations via electric fields, enhancing tunability of spintronic microwave sources.

## Key findings

- Electrostatic gating adjusts excitation currents and spectral features.
- Enhanced effects observed in nonlinear oscillation regimes.
- Electric field influences surface anisotropy and spin-orbit torques.

## Abstract

We study the effects of electrostatic gating on the magnetization auto-oscillations induced by the local injection of electric current into a ferromagnet/heavy metal bilayer. We find that the characteristic currents required for the excitation, the intensity and the spectral characteristics of the generated dynamical states can be tuned by the voltage applied to the metallic gate separated from the bilayer by a thin insulating layer. We show that the effect of electrostatic gating becomes enhanced in the strongly nonlinear oscillation regime at sufficiently large driving currents. Analysis shows that the observed effects are caused by a combination of electric field-dependent surface anisotropy and electric field-dependent contribution to the current-induced spin-orbit torques. The demonstrated ability to control the microwave emission and spectral characteristics provides an efficient approach to the development of electrically tunable microwave nano-oscillators.